The use of communication systems through which to communicate data is an endemic part of modern society. For example, telephonic communication systems have been widely employed and are regularly utilized by a large number of users. Telephonic networks of various telephonic communication systems have been installed throughout significant portions of the populated areas of the world. Telephonic stations are connected to the telephonic network, such as by a wireline connection or a radio interface. A communication session is formed between two or more of the telephonic stations connected to the telephonic network. The telephonic station at which a call is originated may be referred to as the calling party, and the telephonic station at which the call is to be completed, or terminated, may be referred to as the called party.
In most conventional telephonic communication systems, circuit-switched connections are provided between endpoints, i.e., the calling and called parties, during a communication session. When a circuit-switched connection is formed, a dedicated channel is provided to permit the telephonic communications between the telephonic stations that form the endpoints of the communication sessions. For so long as the connection is maintained, telephonic communications between the calling and called parties are permitted. As the data to be communicated pursuant to the communication session might only be communicated intermittently, the communication capacity of the telephonic communication system may not be fully utilized for much of the communication session. Thus, in general, use of circuit-switched connections results in inefficient utilization of the communication capacity of a telephonic network.
Packet-switched communications, in contrast, are able more efficiently to utilize the communication capacity of a communication system. In a packet-based communication system, a common data path can be shared by two or more separate communication sessions. Because packet-formatted data can be communicated during discrete intervals, the same data path can be utilized during separate time periods to communicate packet-formatted data for different communication sessions. More efficient utilization of the communication capacity of the communication system in which the packet-based communication scheme is implemented is thereby possible.
Various packet formatting protocols are used when forming and sending data packets formed of digital data bits. One protocol scheme, the Internet protocol (IP) is regularly utilized in many different communication systems and communication applications. Communication devices constructed to send, receive, transport, and operate upon IP-formatted data can be configured together in a communication system to provide for the communication of IP-formatted data.
Improved telephonic communication systems now being developed include packet data networks through which packet-switched channels may be formed. Typically, gateways are coupled to the packet data network to allow communication between the packet data network and local networks. Thus, when communication from a local network comprises a different type of communication protocol from the protocol used in the packet data network, the gateway coupling the local network to the packet data network performs protocol translation, in addition to other operations such as voice encoding and the like.
Operational control of the telephonic communication system is carried out by a softswitch that functionally forms a part of, or is coupled to, the packet data network. The softswitch operates to control connection services of the gateways and to control call routing based on signaling information and database information related to the calling party and called party.
These improved telephonic networks include various redundancies, such as redundant softswitches, in order to continue providing communication when primary components malfunction or fail. For example, in the event of a communication link failure, conventional communication systems automatically switch to a backup communication link. For this approach, while the primary communication links to the primary softswitch and the primary softswitch itself are functioning properly, communication links to a backup softswitch are placed out of service. Disadvantages associated with this approach include continuous major alarm conditions on signal transfer points for the communication links to the backup softswitch, difficulty in managing the failed communication links, and the possibility of communication links failing while not being used and, therefore, being unavailable when traffic is applied.